Like genocides in Darfur and Rwanda, the massacres in Nigeria that took place at 3 a.m. last night weren't high tech. They were fought with machetes. About 100 suspects have been arrested, but it is hard to tell how authorities would know who was involved.

As the Sahara is expanding Southward, predominantly Muslim herders are being forced South into the territory of subsistance farmers who are predominantly Christian and animist and having a stuggle to survive as the local climate dries. Sudan will hold an independence vote on the issue in January 2011 likely to result in a South Sudan new contry that mostly includes Christians and animists, along this line, although leaving isolated patches of supporters of Southern Sudan that are North of the line like those of the Nuba Mountains( a territory that size of a large county with five language families most of which are part of the farthest Eastern branch of the Niger-Congo languages). This followed long brutal civil war between Northern Muslims and the Southerners.

The basic conflict repeats itself across the Sahel. This rather than Peak Oil, is likely to spawn some very bloody and ruthless conflicts yet to come.

The conflict isn't purely religious, of course. The Northern Muslims in Nigeria and Sudan, for example, both have a large Fulani component, and in Sudan, Nigeria, Niger, and across the Sahel to the West havea large Hasua component. The divides between these two ethnicities, indeed, traceable to medieval African empires, is fading despite linguistic divides (the Fulania speak of Chadic language associated with Afro-Asiatic languages, while the Hasua speak a Niger-Congo language). Both linguistic groups have more than 20 million speakers.

Chrisitians in Nigeria are mostly Anglicans affiliated with the Church of Nigeria, or Roman Catholics.

Religious violence is also common between majority Sunnis and minority Shi'ites in Sokoto State in Nigeria's far Northwest, both of whom are mostly ethnically Hasua. Yoruban Muslims in Southeast Nigeria came to their faith about five hundred years later than Northern Nigeria via expansion of an empire in Mali. About one in nine linguistically Yoruban people are Muslim, while Islam is a predominant religion in the North.